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(No Model.) 3 SheetsSheet 1. D. H. DORSETT.

UNDERGROUND CONDUCTOR.

No. 340,431. Patented Apr. 20, 1886.

INVENTOR ATTORNEY WITNESSES.-

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(No Model.) 8 Sheets-Sheet 2.

D. H. DORSETT.

UNDERGROUND oommo'ron.

No. 340,431. 7 Patented Apr. 20, 1886.

WIT/M58858. "VI/EH70 7mm I y ATTORNEY N. PETKRi Pholo-lilhngmpher, wm m. n c.

(No Model.) 3 Sheets-Sheet 3.

D. H. DORSETT.

UNDERGROUND CONDUCTOR.

"--'"N0.'340,431. Patented Apr. 20, 1886.

Fig. 4.

"Wag/T09 WITNESSES.

ATTORNEY Lil PATENT OEEIcE DANIEL H. DORS ETT, OF- CHICAGO, ILLI'XOTS.

UNDERGROUND CONDUCTOR.

Application filed October 15, 1895. Serial No. 179,901

(No mndclj ICA EION forming part of Letters Patent No. 34OA31, dates; April. 26, 1886.

Patented in England October 20, 195,33). 13109,

To all whom it may concern.-

Be it known that I, DANIEL H. Donsrxrr, a citizen of the United States, residing at (lhicago, in the county of Cool; and State of lllinois, have invented certain new and useful Improvements in Underground Conductors, of which the following is a specification, reference being had to the drawings accompanying and forming a part of the same.

My invention is an improveinentin systcins of underground electric conductors, the inn provement being directed to facilitating the laying and distribution of the conductors throughout a city or any part of the same; to the better insulation of said conductors, and the prevention of inductive or other injurious effects arising from the close proximity of circuits for differentpurposes, such as telegraphing or telephoning on the one hand and electric lighting on the other.

My system is comprehensive and complete in so far as it provides for theeconomieal laying and working of all the circuits which the present needs of business and communication require. In other words, I provide for the running in close proximity of circuits for carrying the strongest and most intense currents, as well as those for carrying the most feeble electrical impulses such as are produced in the operations of telephonyand this in such manner there will be nodangerto any circuit from such proximity, while all are brought within ready and easy access. The system comprises main and branch pipes or conduits, in which the conductors are carried in the manner hereinafter specified. The mains consist of three separate and independ ent pipe-lines, one containing such wires as are required for communication with distant points or other cities, and which will be hereinafter designated as trunk-lines. Another pipe containsthe wires of circuits used iuloca-l communication and intercommunications such as telephone lines, fire and burglar alarm circuits, and the likc--while the third contains the circuits used for electric lighting, transmission of power, or those industrial and domestic applications of electricity which require powerful currents. The lines are run through the streets of a city at such a distance below the surface as will insure protection against bending or injuries from repair of the streets, subsidence of the surface soil, and the like. Generally and whenever convenientthe lines are run midway betweeen the buildngs on either side of the way, and with the trunkline between the other two. At the intersections of the streets the three lines are run into 'what I term man-holes"-that is, subterranean chnmberslarge enough to permit a man to enter them for obtaining access to thepipes or conductors therein. l.hese 1nan-holes are constructed in a way to keep out water and other matter, and are provided with suitable detachable covers. "he pipes pass through their sides, and the wires are carried from one pipe to another, as may be reipiired. Between the man-holes and along the blocks or squares are numeroussubterranezui chambers, which I designate hand-holes. These are placed as nearly as practicable opposite the dividing-lines between the buildings, so that in places where the buildings are of about the same frontage two handlioles are required for each group of four houses, as will shortly be explained.

The hand-holes are for the purpose of running lnanchesl'rom the two pipe lines on either side of the trun leliue, which latter does not pass through them. They are or than the, manholes, though constructed on the same principle. The pipes containing the sigiuiliiig and those with the electric light wires enter theseboxes, and one or more oflhe wires or branches from the same are brought up to a higher level and taken oil into smaller branch pipes to the buildings. Four of the smaller pipes run from each haudliole, one to each of the four nearest buihlings, and in laying the handholes and branches it is desirable to locate the former as near as possible to each other, in order that all the branches may be placed in laying in one small trench. Of the two branch pipes that run to each house,therefore, one contains the wires ofanel etric-light circuit, the other those of a telephone or other signaling circuit. in the case of the former there may be one or more leading and return wires for the same house-circuit, or the leading wire or wires to one house and the return wire or wires from another. This is obviously a matter ofchoiee and not essential to the main features-that ofisolati n g the electriclight circuit from the others.

much smalt- In a former patent, No. 305,904, I have de scribed an underground conduit for electrical conductors made of an insulating compound containing coal-tar, paraffine, silieious sand, pulverized ashes and cinders, oxide of manganese, and ammonium chloride, in about the proportions hereinafter specified. This matei ial I use for the mains of my system, preferring it to all others. The joints between the SG( tions of the pipes may be either of metal, as set forth in the said patent, or the entire conduit may be made from the insulating material alone. I make the man-holes of this material also, their construction being fully described in a patent granted to me July 21, 1885, No. 322,529, except that in the present instance I make them oblong or oval in crosssectiou. The hand-holes are also madeofthis material, their specific construction being hereinafter more fully described.

Inasmuch as the mains are buried deep and are of comparatively large size, they are advantageously made of the insulating compou nd alone; but it is extremely undesirable to bury the branch pipes deep. In fact they should be but little below the surface or flagging of the street, and as they carry usually only one or two wires they should be made quite small.

Instead of making them therefore of the compound alone, I use iron pipes, which I fill with the compound, through which passages are formed for the wires. Ky this means the requisite strength and insulation are obtained.

\Vith this general description of the nature of the system, I will now describe the specific construction and composition of the parts of the same by referring to the drawings annexed hereto.

Figure 1 is a general plan or diagram of a portion of the system as applied to a city or town. Fig. 2 is a vertical central section of one of the manholes. Fig. 3 is a plan view of the same. Fig. 4 is a plan View of a part of the line, exhibiting the arrangement of the hand-holes. Fig. 5 is a broken section of Fig. 4, taken through the centers of the handholes.

Similar letters of reference indicate corresponding parts in the several figures.

In Fig. 1 is illustrated a portion of a city at the intersection of two streets. The underground lines'are laid at or nearthe middle of the street, and are inclosed in the pipes. That indicated in continuous lines is the trunkline, and is lettered A.

The conduit B, in dotted lines, contains the local signaling-circuits, while 0, in broken lines, contains the electric-light and powercircuits.

The three lines or systems are laid in the same trench on the same or different levels,

and preferably with the trunk-line in the center. At the intersection of the streets the three pipes enter man-hole D. The details of the construction of this are shown in Figs. 2 and 3. It is a large box or chamber made of molded slabs or in one piece of the insulating compound described by me in former patents,

and consisting of residuum of partially'distilled coal-tar, parafiine, silieious sand, pulverized ashes and ci'nders, oxide of manganese, and ammonium chloride in about the proportion of fifty gallons of coal-tar, two of paraffine. one hundred and fifty pounds of silieious sand, fifty of ashes and cinders, two pounds of oxide of manganese, and one of ammonium chloride. These i ngredientswhen thoroughly mixed and heated, form a plastic compound, which is molded in the desired shape, and which when cool becomes extremely hard.

The man-holes have a contracted opening -at the top, which is closed by the following means: A metal rim, E, is placed in the mold or on the materialwhile soft. On hardening. the compound adheres to the rim; but it may be secured by other means, if deemed expedient. A crossbar, F, is properly secured in the rim, and the cover is held down by a screwbolt, G, that passes through the cross-bar.

I prefer to make the man-hole oval or oblong in cross-section, as shown in Fig. 3, and to introduce the mains through its broader sides. The mains are made of the same material as the man-hole, and they arejoined to it by passing their ends through holes in its sides and ramming in some of the same material while soft around their 'ends. In each man-hole is a partition, II, or several, if desirable, that extend up above the level of the mains, dividing the space within the manhole into compartments. In one ofthese compartments the electric-light wires enter, so that they are entirely slmt off from the other circuits by awall of insulating material. The mains enter and leave the man-holes on opposite sides; but where it is necessary-to run either trunk-lines or local circuits off on side streets other conduits, K L, are joined to the man-holes, as shown in Fig. 2.

The man-holes permit easy access to all the circuits. The entering wires are here (listributcd to the proper conduits, repairs or tests made, or new circuits introduced. mains are for this purpose made with a certain number of ducts or. passages, a, Fig. 2, through which the wires are drawn.

For running the circuits to the different houses, I use the junction-boxes or hand-holes shown in Figs. 4 and 5. These are connected with the electriclight and local-wire conduits only, and are placed as near together as practicable, in order that the pipes running from them may be laid in the same trench. These hand-holes are made of the same material as the conduits and man-holes, are similar .to them in many respects, and are provided with the same or similar covers. They are much smaller and shallower, however, extendingdown only slightly below the level of the mains. The latter are joined to them in the same manner as to theman-holes.

In the diagram Fig. 1 I have represented the houses and buildings along the street. The division-lines between the buildings are designated by M, and as near as practicaw The just below the service of the street.

ble in line with these two handholes are placed. Tubes run direct from thehand-holes to the buildings. From the hand-holes N on the electric-light conduits run the branch pipes m a and m a, and from the hand-holes O on the local signalingconduit run branches 0 p 0 There will be four branch pipes from each hand-hole, and-they enter them considerably above the level of the mains and Such wires as are necessary are taken up from the mains and carried through these branches. It is desirable that these branches should be small, and that they should be near the surface, but I have found it desirable under these circumstances to make them of stronger materials than are used in, the mains. For this reason I use iron pipes or tubes provided with suitable couplings and filled with the material composing the mains, through which ducts or passages are formed for the wires. My method of making them is to place an iron pipe of the desired length over one or more smaller rods or tubes fixed rigidly at one or both ends. I then fill in the intervening spaces with the hot and soft insulating material, tamping it down to form a solid mass. I then withdraw the rods or tubes and allow the compound to harden. These pipes are joined to the handholes in the same manner that the insulating mains are united to the man or hand holes. As the handholes are only designed to afford access to the wires in one pipe, they are much smaller than the man-holes.

I have thus described the complete system of underground distribution and protection of electric circuits which forms my invention. Of coursein practice the system may or may not be carried out in all its described details. For instance, it is not requisite that branches be carried to every house on a block, as all the buildings may not need or use them; nor is my invention limited to a single pipe for the trunk-line or either of the others, as the necessities of particular cases may require two or even more of one or all the kinds of pipe named. Further, so far as the general plan of distribution is concerned it is largely immaterial how or of what materials the conduits and their appurtenances are made.

The particular advantages which I gain from this method of running underground lines are these: The conductors of different classes of circuits are entirelyisolated from each other, so that injurious electrical inductive dis 1 turbances are reduced to a minimum and the greatest safety assured. At the same time all the lines'are brought into positions of easy access at the man-holes, one of the latter only being required for the three lines.

I do not claim herein any of the elements .or parts of this system as independent instrumentalities, but only in the combinations in which they have here been described as entering and which effect the new and useful results set forth.

In other applications of even date herewith I have claimed both the specific construction of the man-holes and of the branch pipes.

What I new claim is- 1. In an underground system, the combination, with deeply-buried main conduits composed entirely of a plastic insulating material, of branch conduits from the same to the buildings along the way buried nearer the surface of the street or roadway and made of iron pipes filled with an insulating material, as set forth.

2. In an underground system, the combination, with deeply-buried conduits composed entirely of a plastic insulating material, of man-holes placed at the intersections of the streets and molded from the same or similar material, insulating hand-holes or junction boxes placed at intervals along the conduits and branch pipes from the same buried nearer the surface than the mains and made of iron pipes filled with an insulating material, as set forth.

8. In an underground system, the combination, with three deeply-buried and parallel conduits containing, respectively,trunk, localsignaling, and electric-light lines and composed entirely of insulating material, manholes placcd at theintersections of the streets and to which all the conduits are led, handholes placed at intervals along the conduits containing the local-signaling and electric light lines, the man-holes and hand-holes be ing composed of insulating material, and branch conduits from the hand-holes to the buildings buried above the main conduits and near the surface of the street or road and co1nposed of iron pipes with a filling of insulating material provided with ducts or passages for the wires, :as set forth.

DANIEL H. DORSETT.

Witnesses:

Jas. DANIEL COMPTON, PARKER XV. PAGE. 

